Proposal for New Diagnostic Criteria for Sarcopenia Based on CT Imaging in Saudi Population: A Novel Method in Oncology Research

Purpose: Sarcopenia is regarded as a diagnostic and prognostic marker for various diseases and health issues. Several studies have used CT to measure psoas muscle surface area (PMA) to define sarcopenia. However, the cut-off values based on CT imaging remain undetermined in Saudi population. The aim of this study is to provide sex and age-specific percentiles for PMA, psoas muscle index (PMI) and psoas muscle density (PMD) in Saudi population and to establish a formula to calculate the standard PMA based on individual anthropometric measurement.Methods: Pre-operative CT imaging at the third lumbar vertebra level was used to measure PMA, PMI and PMD in 400 adult donors for living donor kidney transplantation. We determined the age and sex -specific cut-off values of PMA in order to define low skeletal muscle mass. A formula was generated to calculate the standard PMA using body weight as the independent variable and further validated on a new dataset involving individuals from the general population.Results: Males had significantly higher measurements of PMA than females (10.7 ± 2.7 cm2 vs 5.8 ± 1.9 cm2). PMA was positively correlated with body weight in both genders. The estimated PMA using the generated formula correlated strongly with the manually traced PMA measurements. The mean differences between estimated and measured PMA values were 0.81 ± 1.70 cm2 among males and 0.17 ± 1.19 cm2 among females. These outcomes emphasize the validity of our predictive computations.Conclusion: Defining population specific cut-off values of PMA and PMI aids in CT based opportunistic screening for sarcopenia.